﻿using System;
using System.Collections.Generic;

namespace MyLibrary
{
    public class PrimeFactorizer
    {
        public string PrimeFactors(int number)
        {
            if (number < 2 || number > 1000)
                throw new ArgumentOutOfRangeException(nameof(number), "Number must be between 2 and 1000.");

            var factors = new List<int>();
            for (int i = 2; i <= Math.Sqrt(number); i++)
            {
                while (number % i == 0)
                {
                    factors.Add(i);
                    number /= i;
                }
            }

            if (number > 1)
            {
                factors.Add(number);
            }


            return string.Join("×", factors);
        }
    }
}